4. As the wound cicatrizes a certain amount of enophthalmos is very liable to result.
EVISCERATION OF THE ORBIT
Indications. This operation is usually performed for some form of new growth originating either in the eye or the orbit.
Operation. This may be modified (1) according to the position of the growth. In severe cases of rodent ulcer and sarcomatous growths, which involve the lids, it is desirable that the lids should be removed with the tumour; but in cases of tumour of the optic nerve, or disease situated far back in the orbit, and not involving the lids or conjunctiva, these structures may be retained, since a much better socket is thus obtained. (2) The nature of the growth. In simple tumours, such as nævi and some cases of arterio-venous aneurism which have failed to yield to other treatment, the incomplete method, in which the lids are retained, is all that is necessary, but in malignant cases they should be removed.
The Complete Method. An incision down to the bone is first made, completely encircling the orbital margin and including any growth that may be involving the skin. The periosteum is then separated completely, as near to the optic foramen as possible. Care must be taken in dealing with the periosteum over the lachrymal bone, as the bone is liable to be fractured and an opening made into the nose if undue force be used. The apex of the cone formed by the periosteum is divided, as far back as possible, with curved scissors, and the whole orbital contents are removed. The wound is packed with gauze, and skin-grafting is subsequently performed when the bone has become covered with granulations; this usually occurs about the end of the second week.
The Incomplete Method. The globe is first enucleated and the outer canthus divided. The lids are well retracted and an incision is carried down to the bone along the orbital margins. The periosteum is then stripped up from the walls of the orbit and the apex of the cone divided as far back as possible, as in the previous operation. The conjunctiva and outer canthus are then united with sutures. As a rule, skin-grafting is not necessary after this operation.
OPENING AN ORBITAL ABSCESS
Orbital abscesses should be incised where they point. In the upper lid care should be taken not to divide the levator palpebræ muscle; the incision should be placed well to one side. In making an incision over the inner side of the orbit care should be taken not to detach the pulley of the superior oblique. The cause of the abscess should be ascertained if possible. Suppuration in the ethmoidal sinuses coming through from the nose is the commonest cause, and should be treated appropriately (see Section V).